Cyanide metabolism in motor neuron disease.

Cyanide concentrations in whole blood, saliva and urine were measured in 83 patients with motor neuron disease (MND) and age-, sex-matched control subjects consisting of 62 patients with and 49 without neurological disorders. Cyanide levels in whole blood and urine of MND patients were significantly higher than the non-neurological control groups in smokers and non-smokers. Cyanide levels in whole blood of MND patients were also higher than the neurologic control group in smokers, but not in non-smokers. There was no significant difference between the cyanide level and either the clinical types or degree of disability of MND. The results suggest that MND patients possess a disorder in cyanide metabolism.